Aluminum Brazing Sheet Cold Rolling for Strong Clad Bonding
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Solution Overview
Problem
Existing methods for producing aluminium alloy brazing sheets face issues such as poor metallurgical bonding, high scrap generation, non-uniform clad layer thickness, and time-consuming processing due to improper bonding and oxide layer formation, limiting flexibility and recyclability.
Innovation Solution
A method involving primary and secondary cold rolling of a laminate structure with controlled roll diameter to thickness ratio and surface treatment to achieve a strong metallurgical bond, fine silicon particles, and reduced scrap generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot rolling is used to create metallurgical bond between core and liner alloy, then bonding is achieved, but mixed alloy scrap is generated that is difficult to recycle
Solution Approach 1:
The invention changes the temperature parameter from hot rolling (400-500°C) to cold rolling (room temperature), fundamentally altering the bonding mechanism. This parameter change eliminates the formation of mixed alloy scrap while achieving equivalent metallurgical bonding through diffusion at lower temperatures, directly resolving the contradiction between bonding reliability and scrap generation.
2Manufacturing precision
If cleaning and welding are performed to prepare clad package, then bonding surface is prepared, but processing time increases and product cost increases
Solution Approach 1:
The invention extracts and eliminates the welding step from the traditional cleaning-welding-bonding sequence. By using cold rolling to directly bond the cleaned surfaces, the time-consuming welding operation is removed entirely, reducing processing time and cost while maintaining bonding surface preparation quality.
Solution Approach 2:
The invention merges the cleaning and bonding operations into a single integrated process. The surfaces are cleaned and then immediately bonded through cold rolling without intermediate welding steps, consolidating multiple operations into one efficient sequence that reduces overall processing time.
3Temperature
If pre-heating is performed before bonding, then bonding temperature is achieved, but thick oxide layers form that adversely affect diffusion bonding
Solution Approach 1:
The invention inverts the traditional approach by performing bonding at cold temperatures instead of heating to high temperatures. This reversal of the temperature parameter prevents oxide layer formation entirely, as the low temperature conditions do not promote oxidation, while still achieving effective diffusion bonding through the cold rolling process.
4Loss of time
If cold rolling is used to bond core and cladding sheets, then processing time is reduced, but proper bonding may not be achieved without controlled parameters
Solution Approach 1:
The invention identifies and controls critical parameters for cold rolling bonding including roll surface temperature, rolling pressure, and surface preparation quality. By optimizing these parameters, the process achieves reliable metallurgical bonding through diffusion at room temperature, maintaining bonding quality while significantly reducing processing time compared to traditional hot rolling methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Results in aluminium brazing sheets with enhanced bond strength, uniform clad layer thickness, improved brazability, and significantly less mixed alloy scrap, facilitating efficient processing and recycling.
Implementation Method 1
cold rolling the core sheet with the cladding sheet so as to roll bond them to make a composite aluminium sheet
Data Source
AI summary
Provided herein is a method for making aluminium brazing sheets comprises of, a) providing a core of first aluminium alloy; b) cladding said core, on one or two sides, with a second aluminium alloy, forming a laminate structure; c) performing a primary cold rolling of said laminate structure so as to roll bond core and cladding 5 alloy of said laminate structure; and d) performing at least one secondary cold rolling step of roll bonded laminate structure to obtain aluminium brazing sheet of desired thickness.